Lifejacket

ABSTRACT

An inflatable lifejacket including a chamber having a main portion and a head lifting portion, wherein the head lifting portion has a lower elastic modulus than the main portion. In the embodiment: the chamber has a front side and a back, water-facing, side, the head lifting portion being located in the back side, with the front side supporting a wearer&#39;s head; the main portion is substantially inextensible and/or substantially inelastic; and at least one inflatable bladder is located inside the chamber.

TECHNICAL FIELD

The present invention relates to a lifejacket having a chamber that is configured to be buoyant by inflation in use.

BACKGROUND TO THE INVENTION

A problem with known lifejackets is that, in use, water tends to flow into a wearer's mouth particularly in rough seas with wind and waves which can cause drowning, especially if a wearer is unconscious. Factors that influence this are:

-   -   The HOM (Height of Mouth). This is vital in achieving survival         and the height of the mouth from the water surface has to be a         minimum of 120 mm to comply with current regulated standards.     -   The FPA (Face Plane Angle). If the FPA is too shallow (e.g. less         than) 25° then waves can wash over the mouth and cause choking         (dry drowning) and if it is too steep then the subject cannot         breathe properly.

Embodiments of the present invention seek to provide an improved lifejacket that addresses this problem.

SUMMARY OF THE INVENTION

According to the present invention there is provided an inflatable life jacket including a chamber having a main portion and a head lifting portion, wherein the head lifting portion has a lower elastic modulus than the main portion.

The main portion may comprise the majority of the surface area of the chamber, and may form at least 75% of the surface area of the chamber.

The chamber may be inflatable.

Advantageously, the arrangement may be such that the head lifting portion deforms by a greater amount than the main portion in response to inflation force. This may provide greater buoyancy at the head lifting portion.

In the embodiment the chamber has a front side and a back—water-facing (in use)—side, the head lifting portion being located in the back side. The head lifting portion is therefore generally in contact with water in use. Its greater buoyancy pushes the front side in the region opposite the water-facing side upwardly away from the water, and this tilts and lifts the head of the wearer upwardly, and may increase the face plain angle (FPA) and the height of mouth (HOM) above the water—and therefore improves safety.

The main portion may be substantially inextensible and/or substantially inelastic. When inflated, the main portion creates a firm/generally rigid surface to provide support for the wearer. In contrast, the relatively extensible and elastic head lifting portion expands and provides localised greater buoyancy where it is in contact with the water.

In one embodiment the chamber is directly inflatable.

Alternatively at least one inflatable bladder may be located inside the chamber. In one embodiment to be described two inflatable bladders are located inside the chamber. In an alternative arrangement the bladder has two separate chambers. Advantageously, the bladder is confined by the chamber so that, when inflated, the bladder is untensioned, the tension being taken by the chamber. In the embodiment the bladder is of a size such that it does not stretch when inflated but unfolds to fill the chamber and presses against the interior of the chamber. In the embodiment, as the main portion of the chamber is substantially inextensible and/or substantially inelastic, this constrains the expansion of the bladder. Because the head lifting portion is relatively extensible and relatively elastic, the inflation of the bladder does cause deformation of the chamber in this region in order to provide localised increased buoyancy.

The chamber may include a liquid permeable portion for allowing liquid to drain therefrom. The provision of a liquid permeable portion can be advantageous when water has entered the chamber, as it allows that water to drain from the chamber. Water may enter the chamber through the head lifting portion if this is formed of a liquid permeable material. The liquid permeable portion may be formed of the same type of material as the head lifting portion. In this arrangement the surface area of the chamber may consist of the liquid permeable portion, the head lifting portion and the main portion, the main portion forming at least 75% of the surface area of the chamber.

In one embodiment the chamber is generally U-shaped or horse-shoe shaped. The chamber includes two leg parts extending from opposite ends of a connecting part, which connecting part may support the wearer's head in use. The head lifting part extends between the leg parts and the connecting part.

In another embodiment the chamber has a single lobe part extending from a support part, which support part may support the wearer's head in use. The head lifting part extends between the lobe part and the support part.

The chamber may include at least one narrowed region to facilitate the wearer moving their head to look upwardly and/or sideways. This can be particularly advantageous when the life jacket is worn before the wearer enters the water, for example when descending by parachute with the life jacket donned. The narrowed region may be between each of the leg parts and the connecting part to facilitate the wearer moving their head to look sideways to the left or to the right. Alternatively, or additionally, the chamber may include a narrowed region at the centre of the connecting part to facilitate the wearer moving their head to look upwardly.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a front view of a lifejacket in accordance with an embodiment of the invention;

FIG. 2 shows a rear view of the life jacket of FIG. 1;

FIG. 3 shows a side perspective view of the life jacket worn around the neck of a model wearer;

FIG. 4 shows a cross section taken along the line X-X of FIGS. 1 and 2;

FIG. 5 shows a life jacket in accordance with the embodiment of the invention deployed on water;

FIG. 6 shows a life jacket without the head lifting portion of the embodiment when deployed on water; and

FIG. 7 shows an alternative embodiment for providing an expanding panel.

In the drawings like elements are generally designated with the same reference sign.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Referring initially to FIGS. 1 to 4, there is shown a lifejacket 1 according to a first embodiment of the invention. The lifejacket comprises a body or chamber 3 that is generally horse-shoe shaped and is for fitting around a wearer's neck 5. The life jacket body 3 is rendered buoyant in use by inflation. When inflated, each buoyancy section 7, 9 is an elongate member of generally oval transverse cross-section.

The body 3 comprises first and second buoyancy sections 7 and 9 which form two legs of the horse-shoe, arranged to lie on opposite sides of a wearer's chest. The legs may be disposed symmetrically to lie on opposite sides of a wearer's chest (although this is not essential). First ends of the first and second buoyancy sections 7, 9 are joined together by a connecting neck portion 11. The first and second buoyancy sections 7, 9 each extend from said first end to a second end 13, which is a free, distal end. The first and second buoyancy sections 7, 9, together with the connecting neck portion 11, define an aperture 15 for receiving a wearer's head and neck 5.

The lifejacket body 3 is formed from front and rear layers 17 and 19 attached together along a seam 21, towards a peripheral edge, to define a body/chamber 3.

The front layer 17 is made from a strong but lightweight material, and it is preferably of a high visibility colour. The rear layer 19 is mainly formed of the same or a similar strong but lightweight material, that is also preferably of a high visibility colour. The material used for the front and/or rear layers 17 and/or 19 may, for example, be a woven polyester or polyamide.

The front and rear layers 17 and 19 are preferably attached to each other along the seam 21 by stitching (although other attachment techniques, such as welding, may be used alternatively or additionally).

Various attachments may be made to the front and rear layers 17 and 19. For example, the front layer 17 may have stitched to it lights 23. The rear layer 19 may have attached to it by stitching belt loops 25. In addition, patches may be attached to the life jacket body 3 to fix whistles, radio aerials and the like. A strap 26 is attached to the rear layer 19 (e.g. by stitching), and this may be used to attach the life jacket 1 to another garment worn by the wearer or to a waist belt. The belt loops 25 may receive a waist belt of the other garment in order to help secure the life jacket 1 to the garment (and the wearer).

The rear layer 19 includes a head lifting portion 27 that is formed of a different material to the main part 28 of the rear layer 19. The head lifting portion 27 is formed of a material that has a lower modulus of elasticity than the main part 28 of the rear layer 19, and preferably also a lower modulus of elasticity than the front layer 17. The head lifting portion 27 may comprise a stretch netting comprising elastane or spandex (or similar) threads, but could be made from other types of elastic material.

The front layer 17 and the main portion 28 of the rear layer 19 may be formed of a material that is substantially inextensible and/or inelastic. The front layer 17 and the main portion 28 of the rear layer 19 may present a substantially rigid or firm surface when inflated.

The head lifting portion 27 has a lower elastic modulus than other parts of the body 3. That is, the force required to elastically deform the head lifting portion 27 is less than the force required to elastically deform other parts of the body 3.

The rear layer 19, in addition to the main portion 28 and the head lifting portion 27, may also include a drainage area 29 at the distal end 13 of each of the buoyancy sections 7 and 9. The drainage portions 29 are liquid permeable. The drainage portions 29 may be formed of the same material as the head lifting portion 27. Although in FIGS. 2 and 3 of the drawings the drainage part 29 is formed only in the rear layer 19, the drainage part may also, or alternatively, be formed in the front layer 17. FIG. 4 shows the drainage part 29 formed in both the front layer 17 and the rear layer 19.

The head lifting portion 27 and the drainage portions 29 may be attached to the rear layer 19 by stitching, and may be attached to the front layer 17 along the seam 21 also by stitching. These parts may additionally or alternatively be attached in any other suitable manner (such as by welding or gluing).

The body 3 of the life jacket 1 has a first lobe 31 extending from the top of the connecting neck portion 11 that is generally aligned with the first buoyancy section 7, and a second lobe 33 extending from the top of the connecting neck portion 11 on the same side as the second buoyancy section 9. At the top of the neck portion 11, between the lobes 31 and 33, a narrowed top region 35 of the body 3 is provided. The narrowed top region 35 may be narrow in height (in a plane parallel to the seam 21) and in thickness (in a plane perpendicular to the seam 21). The narrowed top region 35 facilitates the tilting of a wearer's head backwards when the lifejacket is inflated.

The body 3 additionally comprises a first narrowed side region 37 between the first lobe 31 and the first buoyancy section 7 and a second narrowed side region 39 between the second lobe 33 and the second buoyancy section 9. These narrowed side regions 37 and 39 may be narrowed in width (in a plane parallel to the seam 21) and in thickness (in a plane perpendicular to the seam 21). The narrowed side regions 37 and 39 facilitate a wearer of the life jacket to turn their head sideways, to the left or right when the lifejacket is inflated.

The narrowed regions 35, 37 and 39 are particularly advantageous when the life jacket 1 is worn and inflated prior to the wearer entering water. Prior to the wearer entering water the life jacket may lie against the wearer's shoulders and chest as shown in FIG. 3, and in this position, the narrowed portions 35, 37 and 39 allow the user to tilt their head backwards and to turn their head sideways. The narrowed portions 35, 37 and 39 are configured so that a pilot wearing a helmet and suspended under a parachute can look upwards and sideways while he adjusts the parachute risers.

In a preferred arrangement, to be described in more detail below, one or more bladders is provided inside the body 3, and the bladders are directly inflated, rather than the body 3 itself.

In the embodiment illustrated, two bladders 41 and 43 are provided within the body 3, as best seen in FIG. 4, which is a cross-section taken along the line X-X of the FIGS. 1 and 2. Each of the bladders preferably is generally horse-shoe shaped for convenience of mounting the bladder within the body 3 (which is also horse-shoe shaped).

The bladders may be formed of thermoplastic material, preferably a weldable thermoplastic (e.g. polyurethane) coated fabric such as nylon or polyester.

Typically, a front and rear layer of thermoplastic material is cut to the desired horse-shoe shape, and the edges are welded together to form a gas-tight connection. Bladders may also be formed of a polymer coated fabric (e.g. neoprene) and the edges joined together by an adhesive.

Although the bladders 41 and 43 may be of generally the same shape as the body 3, the bladders 41 and 43 may be of generally larger size. The bladder may be made of a sufficiently large size so that, when inflated within the body 3, the bladder fills the internal volume of the body 3 without any stretching of the bladder occurring, and the tension is taken up by the front and rear layers 17 and 19 of the body 3 and the seam, 21 between the front and rear layers 17 and 19. If the bladder is made oversized, the bladder may be made of an inextensible and/or inelastic material.

It is advantageous for the tension to be taken up by the front and rear layers 17 and 19, and the stitched seam 21, as these are stronger than the welded seams of the bladder.

In the embodiment shown in FIG. 4, two identically shaped and sized (that is, uninflated size) bladders 41 and 43 are provided. When either of the bladders 41, 43 is inflated it is able to fill the space inside the body 3. Two bladders 41, 43 are provided to provide 100% redundancy, so that if one bladder is punctured, then the other will fill the space within the body 3 and provide the required buoyancy.

In order to assemble the life jacket 1, the rear layer 19 of the body 3 is laid out flat on a surface. The front layer 17 is then placed over the rear layer 19, and the front and layers 17 and 19 are then stitched together along the seam 21.

In a separate operation the second bladder 43 is laid on top of the first bladder 41. At a side corresponding to the first buoyancy section 7, at the first narrowed section 37, the distal ends of each of the bladders 41 and 43 are both rotated together through 180 degrees so that they are twisted at a cross-over point 45. As a result, in the first buoyancy section 7, the uppermost bladder is bladder 43 and in the opposite buoyancy section 9 the uppermost bladder is the bladder 41 when the bladders are positioned in the body 3.

The assembled bladders 41 and 43 are then passed into the chamber (defined between the front layer 17 and the rear layer 19) through an opening in the front layer 17. In the drawings this opening is shown closed by a zipper 65. The opening could also be closed by press studs, Velcro or the like. The bladders 41 and 43 may be held in place within the chamber 3 by internal tabs with press studs within the chamber 3 which cooperate with corresponding press stud parts on the bladders 41 and 43. Alternatively,

Velcro tabs may be used within the chamber 3 and on the bladders 41 and 43 to secure the bladders 41 and 43 in position.

Such an arrangement allows the bladders 41 and 43 to be replaced or serviced if required—for example, if they are punctured. The bladders 41 and 43 can be removed by opening the zipper 65 and withdrawing them through the opening in the front layer 17.

Some folding of the bladders 41 and 43 may be required to fit them in the chamber (due to the bladders 41 and 43 being oversized).

The bladders 41 and 43 may be inflated manually or automatically. Each of the bladders 41 and 43 includes a gas cylinder 47 that is located within the bladder. The gas cylinder 47 may contain carbon dioxide (CO₂) or any other suitable inflation gas that is stored under pressure. Each of the gas cylinders 47 is connected, through an opening in the rear layer 19, to an inflation unit 49. Inflation unit 49 may detect when it contacts water and automatically trigger operation of the associated gas cylinder 47 to inflate the associated bladder 41 or 43. Inflation unit 49 may also allow a wearer to manually trigger operation of the gas gas cylinder 47 to inflate the associated bladder 41, 49.

Each of the bladders 41, 43 also includes an oral inflation tube 51 which extends through an opening in the front layer 17. The oral tubes 51 allow oral inflation by the user. This can be useful to top up one of the bladders 41, 43 in the event that the other of the bladders is punctured. The crossing over of the bladders 41, 43 at the cross-over point 45 allows the oral tube 51 for each of the bladders 41, 43 to be located in the front layer 17 so that they can be reached easily by the wearer.

As an alternative to providing two separate bladders 41, 43, a single bladder element may be provided that has two separate chambers divided by a baffle that extends generally in the same plane as the stitching 21. This arrangement provides two separate chambers and so also redundancy if one of the chambers is punctured. The baffle is preferably made of the same material as the rest of the bladder element.

If redundancy is not required, a single, unitary bladder may be provided.

In use, the lifejacket 1 is donned by a wearer in an uninflated condition with the neck of the wearer passing through the neck opening of the lifejacket 1.

If the wearer enters the water the inflation system is actuated automatically or the wearer actuates the inflation system by operating the inflation unit 49 so that a valve allows air from the cylinder 47 to enter and inflate the bladders 41, 43. The body 3 is made buoyant by inflation.

In the embodiment, one or both of the bladders 41, 43 are inflated and consequently press against the interior of the body 3. Due to the inextensibility and inelasticity of the front layer 17 and the main portion 28 of the rear layer 19, these parts become generally rigid and form a firm surface that rests against the wearer's chest 60 and against the back 62 of the wearer's head 64.

However, the head lifting portion 27 is relatively extensible and/or relatively elastic. The pressure exerted by the inflated bladders 41, 43 causes the head lifting portion 27 to expand and increase its surface area and therefore its volume. This increases the immersed buoyancy in the area behind the head 64 of the wearer and pushes the front layer 17, in the region opposite the head lifting portion 27, towards the rear 62 of the wearer's head 64, lifting the head further above the water and tilting the head forward into a more upright position. In other words, as the head lifting portion 27 differentially expands it raises the head 64 of the wearer as seen in FIG. 5. As a result of the head being raised, the mouth of the wearer is higher above the water level and this increases the angle of the face plane of the wearer relative to the body pane angle of the wearer so that face of the wearer is in a more upright position.

FIG. 5 shows the face plane angle (FPA) that is the result of the head lifting position 27 expanding relative to the other parts of the body 3. The face plane angle, the angle between the front of the face and the surface of the water is greater than 25 degrees, and this reduces the likelihood of waves washing over the mouth of the wearer and causing choking (dry drowning), but not such a large angle that this inhibits breathing. This is to minimise the possibility of choking that can occur if the face plane angle is too shallow. This may be particularly important should the wearer lose consciousness. As a result of increased buoyancy behind the head this increases the height of mouth (HOM) above the water. The HOM is greater than 120 mm.

As a result of the head lifting portion 27, the volume of the body 3 in the area behind the wearer's head 64 increases by greater proportion than the general volume of the body 3, and so provides localised increased buoyancy behind the wearer's head 64.

A life jacket 1A of the same general form as a life jacket 1 shown in FIGS. 1 to 5, is shown in FIG. 6. However, the life jacket 1A does not include the head lifting portion that is relatively extensible and/or elastic. Localised differential expansion therefore does not occur. As can be seen, the FPA and the HOM are less in the FIG. 6 arrangement.

As an alternative to the bladders 41 and 43 being provided within the chamber 3, FIG. 7 shows an alternative embodiment in which the lifejacket comprises a body of 3A that is itself directly inflatable. The body 3A may be a single chamber having a general horse-shoe shape substantially the same as the body 3 shown in the first embodiment.

The body 3A may define a single chamber for receiving inflation gas, or may have a central baffle 66 as shown in FIG. 7 that divides the body 3A into two separate chambers 41A and 43A. The chambers 41A and 43A (or single chamber) may be inflated manually or automatically. Each of the chambers include a gas cylinder 47A which contains carbon dioxide or any other suitable inflation gas stored under pressure. Each of the gas cylinders 47A is connected, through an opening in the wall of the body 3A to an inflation unit 49A that operates in the same way as the inflation unit 49 of the first embodiment.

Each of the chambers 41A and 43A may also include an oral inflation tube 51A which extends through an opening in the opposite side of the body 3A to the inflation unit 49A. The oral tube 51A allows oral inflation by the wearer.

The body 3A comprises a main part 28A and a head lifting portion 27A that has a lower modulus of elasticity than the main part 28A. The difference in the modulus of elasticity between the head lifting portion 27A and the main part 28A may be the same as the difference between the modulus of elasticity of the head lifting portion 27 and the main part 28 of the first embodiment.

The head lifting portion 27A and the main part 28A are formed of gas impermeable material or substantially gas impermeable material to prevent the body deflating due to the escape of gas.

The body 3A may have various attachments thereto, such as the belt hoop 25A shown.

The body 3A may be formed in two or more parts that are welded or adhered together. The main part 28A of the body 3A may be made from the same material as the bladders 41 and 43 of the first embodiment.

As in the first embodiment, if the wearer of the lifejacket enters the water the inflation system may be activated automatically or the wearer may activate the system by operating the inflation unit 49A. As inflation occurs, the main portion 28A, due to its inextensibility and inelasticity, becomes generally rigid to form a surface that rests against the wearer's chest 60 and against the back 62 of the wearer's head 64.

However, the head lifting portion 27A is relatively extensible and/or relatively elastic. The pressure exerted by the inflation gas causes the head lifting portion 27A to expand and increase its surface area and therefore its volume.

This increases the immersed buoyancy in the area behind the head 64 of the wearer and pushes the front layer of the body in the region opposite the head lifting portion 27A towards the rear 62 of the wearer's head 64, lifting the head further above the water and tilting the head forward into a more upright position, as in the first embodiment.

In the embodiments described above, the lifejacket comprises a body or chamber that is generally horse-shoe shaped and comprises first and second buoyancy sections which form two legs of the horse-shoe, arranged to lie on opposite sides of a wearer's chest.

As an alternative to such an arrangement, a single front lobe may be provided that lies centrally on the chest of the wearer in use rather than two separate legs. A neck portion similar to the neck portion 11 is provided. A generally circular or elliptical aperture is provided to allow the wearer's head to pass through between the neck portion and the front lobe, in order to don the lifejacket.

A head lifting portion like the head lifting portion 27 is provided in the same position as in the embodiments as previously described and operates in the same manner. Narrowed regions may be provided in a similar position to narrowed regions 35, 37 and 39 of the previous embodiments.

In this single lobe embodiment the chamber may be directly inflatable or may have one or more bladders provided therein, in the same general manner as the other embodiments.

The material used for the head lifting portion 27/27A may have any or all of the characteristics listed in the following table:

METHOD OF TEST BS 4952 Section 2 BS 4407 BS EN 1773 BS EN 12127 Method 2.1 Method 2.2 Method 18 BS EN 25077 Width Mass Stretch under Modulus Composition Dimensional stability (usable) Per unit area 35N load at 40% (shrinkage) extension AFTER 1 cycle BS EN 26330 Wash 2A/Dry E (60° C./Tumble) % N % cm g/m² ±15 Minimum % maximum Minimum ±5% Warp Weft Warp ±3 Warp Weft 220 375 75 80 17 + 10% Nylon 77 5 10 Elastane 23

The above embodiments are described by way of example. Many variations possible without departing from the invention. 

What is claimed is:
 1. An inflatable lifejacket including a chamber having a main portion and a head lifting portion, wherein the head lifting portion has a lower elastic modulus than the main portion.
 2. The lifejacket of claim 1, wherein the chamber has a front side and a back, water-facing, side, the head lifting portion being located in the back side.
 3. The lifejacket of claim 2, wherein the front side is configured to support a wearer's head.
 4. The lifejacket of claim 1, wherein the main portion is substantially inextensible and/or substantially inelastic so as to be substantially inextensible.
 5. The lifejacket of claim 1, wherein the chamber is inflatable.
 6. The lifejacket of claim 1, further including at least one inflatable bladder located inside the chamber.
 7. The lifejacket of claim 1, further including two inflatable bladders located inside the chamber.
 8. The lifejacket of claim 6, wherein the bladder has two separate chambers.
 9. The lifejacket of claim 6, wherein the bladder is confined by the chamber so that, when inflated, the bladder is untensioned, the tension being taken by the chamber.
 10. The lifejacket of claim 1, wherein the chamber further includes a liquid permeable portion configured to allow liquid to drain therefrom.
 11. The lifejacket of claim 10, wherein the liquid permeable portion is formed of the same type of a material as the head lifting portion.
 12. The lifejacket of claim 1, wherein the chamber includes at least one narrowed region to facilitate a wearer moving their head to look upwardly and/or sideways.
 13. The lifejacket of claim 1, wherein the chamber is generally U-shaped and includes two leg parts extending from opposite ends of a connecting part.
 14. The lifejacket of claim 13, wherein the head lifting portion extends between the leg parts and the connecting part.
 15. The lifejacket of claim 14, wherein the chamber includes at least one narrowed region between the leg parts and the connecting part to facilitate the wearer moving their head to look sideways.
 16. The lifejacket of claim 14, wherein the chamber includes a narrowed region at the a center of the connecting part to facilitate the wearer moving their head to look upwardly.
 17. The lifejacket of claim 1, wherein the chamber has an aperture configured to allow a wearer's head and neck to pass therethrough, a portion of the chamber on a first side of the aperture configured to support the wearer's head in use and a portion of the chamber on a second, opposite side of the aperture lying on the wearer's chest in use.
 18. The lifejacket of claim 17, wherein the portion of the chamber on the second side of the aperture has the form of a single lobe.
 19. The lifejacket of claim 17, wherein the chamber includes at least one narrowed region between the portion of the chamber on a first side of the aperture and the portion of the chamber on a second side of the aperture to facilitate the wearer moving their head to look sideways.
 20. The lifejacket of claim 17, wherein the chamber includes a narrowed region at the a center of the portion of the chamber on a first side of the aperture to facilitate the wearer moving their head to look upwardly. 